Packing box



FIG. 1 is a front view of a packing box embodying our design;

FIG. 2 is a top plan view of the packing box, the bottom plan view being identical thereto;

FIG. 3 is a right side view of the packing box;

FIG. 4 is a left side view of the packing box; and

FIG. 5 is a rear view of the packing box. 

The ornamental design for a packing box, as shown and described. 